Activity results in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of ActivityResultLauncher in Android Kotlin?

It is used to launch another activity and receive a result back asynchronously, replacing the older startActivityForResult method.

beginner

How do you register for an activity result in Android Kotlin?

You use registerForActivityResult() with an ActivityResultContract and a callback to handle the result.

intermediate

What is an ActivityResultContract?

It defines the input type needed to start an activity and the output type returned as a result, helping to standardize communication between activities.

intermediate

Why is the new activity result API preferred over startActivityForResult?

Because it is lifecycle-aware, safer, and easier to manage results without overriding onActivityResult.

beginner

What happens if you try to launch an activity result without registering the launcher first?

The app will crash or the result will not be delivered because the launcher is not initialized to handle the result callback.

Which method replaces startActivityForResult in modern Android Kotlin development?

A launchActivity

B startActivity

C onActivityResult

D registerForActivityResult

registerForActivityResult is the new recommended way to launch activities for results.

What is the role of the callback passed to registerForActivityResult?

A To handle the result returned from the launched activity

B To start the activity

C To register the activity in the manifest

D To create a new activity instance

The callback receives the result data when the launched activity finishes.

Which class defines the input and output types for activity results?

A Bundle

B Intent

C ActivityResultContract

D ActivityResultLauncher

ActivityResultContract specifies how to create the intent and parse the result.

What lifecycle benefit does the new activity result API provide?

A It is lifecycle-aware and avoids memory leaks

B It runs on a background thread

C It automatically restarts the activity

D It disables lifecycle callbacks

The API respects the lifecycle of the component to prevent leaks and crashes.

How do you launch the activity after registering the launcher?

A Call <code>startActivityForResult()</code>

B Call <code>launch()</code> on the <code>ActivityResultLauncher</code>

C Call <code>onActivityResult()</code>

D Call <code>registerForActivityResult()</code> again

You use the launch() method on the registered launcher to start the activity.

Explain how to use the new activity result API in Android Kotlin to get data back from another activity.

Think about how you prepare, start, and receive results from another screen.

Describe the advantages of the new activity result API compared to the old startActivityForResult method.

Focus on safety and ease of use improvements.